1. Field of the Invention
The present invention relates to a container changing system and a container changing method, and more particularly, to a container changing system, which changes a container that accommodates substrates with a new container, in a substrate processing apparatus.
2. Description of the Related Art
In semiconductor device manufacturing factories, semiconductor wafers (hereinafter just referred to “wafer(s)”) are conveyed between a plurality of substrate processing apparatuses in a clean room. The wafers, when conveyed, are accommodated in a container, such as a FOUP (front opening unified pod), for isolating the wafers from outside in order to prevent dust floating in the clean room from attaching to the wafers.
As shown in FIG. 7, a clean room is typically arranged with a plurality of substrate processing apparatuses 10, stockers 12 for stocking a plurality of FOUPs 11, which will be described later, and rails 13 which are disposed on a ceiling portion of the clean room to link the substrate processing apparatuses 10 and the stockers 12.
Each substrate processing apparatus 10 includes: a loader module 15 having FOUP stages 14 for mounting the FOUP 11 and transferring wafers which are not yet processed (hereinafter referred to “unprocessed wafers”) out of the mounted FOUP 11 or transferring processed wafers into the FOUP 11; process modules 16 for subjecting wafers to plasma processing and the like; a transfer module 17 for transferring a wafer from/to each process module 16; and a load lock module 18 for transferring wafers between the transfer module 17 and loader module 15.
The rail 13 is laid above the FOUP stages 14 in each of the substrate processing apparatuses 10. A plurality of FOUP conveying units 19 (e.g., see Japanese Laid-Open Patent Publication (Kokai) No. 2000-150622), which will be described later, are arranged on the rail 13 to convey the FOUPs 11. Specifically, the FOUP 11 accommodating unprocessed wafers is conveyed out of the stocker 12 to the substrate processing apparatus 10, and the FOUP 11 accommodating processed wafers is conveyed from the substrate processing apparatus 10 into the stocker 12.
FIGS. 8A and 8B schematically illustrates the configuration and operation of a conventional FOUP conveying unit. FIG. 8A is an illustration as viewed from the side of a loader module, and FIG. 8B is an illustration as viewed from the front of the loader module.
In FIGS. 8A and 8B, the FOUP conveying unit 19 includes: a carrier (running body) 20 which is guided by the rail 13 and runs along the rail 13; a holder 21 which is provided below the carrier 20, with a hook being incorporated therein; and a belt 22 which couples the carrier 20 and the holder 21, and is retractable in a floor-ceiling direction in a clean room.
The FOUP 11 is a box-like container made of resin, which accommodates a plurality of, e.g. 25 wafers so as to be disposed parallel to each other. The FOUP 11, whose one side face is structured by a cover member that can be opened and closed, is provided with a portion 23 to be held (hereinafter referred to “holding portion 23”) having a projected portion projected from a ceiling portion, which projected portion has a tip end formed into a tabular shape.
In the FOUP conveying unit 19, the holder 21 is able to hold the FOUP 11 by having the incorporated hook engaged with the holding portion 23 of the FOUP 11. Meanwhile, the belt 22 lifts up/down the holder 21 in the arrowed direction indicated in FIGS. 8A and 8B by having the belt 22 expanded and contracted. As a result, the FOUP 11 held by the holder 21 is lifted up/down between the carrier 20 and the FOUP stage 14. In conveying the FOUP 11, the FOUP conveying unit 19 contracts the belt 22 to lift up the FOUP 11, and moves in the state where the FOUP 11 is suspended.
In the case where the FOUP 11 accommodating processed wafers is changed with the FOUP 11 accommodating unprocessed wafers in the substrate processing apparatus 10, the (empty) FOUP conveying unit 19 without suspending the FOUP 11 first moves to the substrate processing apparatus 10, lifts up the FOUP 11 accommodating the processed wafers from the FOUP stage 14, and conveys the FOUP 11, in the state of being suspended, to the stocker 12. Then, the FOUP conveying unit 19 suspends the FOUP 11 accommodating unprocessed wafers from the stocker 12, and in this state, conveys the FOUP 11 to the substrate processing apparatus 10, and lifts down the FOUP 11 for mounting on the FOUP stage 14.
However, the substrate processing apparatus 10 and the stocker 12 are typically disposed being distanced from each other. For this reason, it takes time to convey the FOUP 11 between the substrate processing apparatus 10 and the stocker 12, using the FOUP conveying unit 19. In addition, the substrate processing apparatus 10 cannot process the wafers during the conveyance in which the FOUP conveying unit 19 conveys the FOUP 11 accommodating processed wafers from the substrate processing apparatus 10 to the stocker 12 and subsequently conveys the FOUP 11 accommodating unprocessed wafers from the stocker 12 to the substrate processing apparatus 10. As a result, working rate of the substrate processing apparatus 10 is deteriorated.
In order to enhance the working rate of the substrate processing apparatus 10 by omitting the conveyance of the FOUPs 11 between the substrate processing apparatus 10 and the stocker 12, a method has also been suggested, in which the number of the FOUP stages 14 of the substrate processing apparatus 10 is increased so that the substrate processing apparatus 10 can temporarily stock the FOUPs 11 accommodating processed wafers and the FOUPs 11 accommodating unprocessed wafers.
However, the FOUP conveying unit 19 is capable of mounting the FOUP 11 on the FOUP stage 14 only from above. Meanwhile, the increased FOUP stages 14 are required to be disposed in the horizontal direction with respect to other FOUP stages 14, which will increase the floor area (foot print) occupied by the substrate processing apparatus 10. As a result, the number of the substrate processing apparatuses 10 that can be arranged in the clean room is decreased to decrease the amount of production of the semiconductor devices.
There is a strong tendency, in the future, that semiconductor devices tend to be increased in the types and decreased in the amount of production for each type. Accordingly, the number of changes of the FOUPs 11 in each substrate processing apparatus 10 is expected to be increased. For this reason, the problems described above may become more apparent.